Solar cells are well-known devices for converting solar radiation to electrical energy. They may be fabricated on a semiconductor wafer using semiconductor processing technology. Generally speaking, a solar cell may be fabricated by forming n-type and p-type diffusion regions in a silicon substrate. Solar radiation impinging on the solar cell creates electron-hole pairs that migrate to the diffusion regions, thereby creating voltage differentials between the diffusion regions. In a back-contact solar cell, both the diffusion regions and the metal grids coupled to them are on the back side of the solar cell. The metal grids allow an external electrical circuit to be coupled to and be powered by the solar cell.
Efficiency is an important characteristic of a solar cell as it is directly related to the solar cell's capability to generate power. Accordingly, techniques for increasing the efficiency of solar cells are generally desirable. Embodiments of the present invention will be recognized by those skilled in the art as improved back-contact cell structures that allow for advantages in both efficiency and manufacturing cost compared to conventional solar cells.